Origin

Native to tropical Africa, Madagascar and some islands in the western Indian Ocean (Mauritius and the Seychelles)

Cultivation

Crab's eye creeper (Abrus precatorius subsp. africanus) has
been widely cultivated as a garden ornamental, largely because of its attractive
and decorative bright red and black coloured seeds.

Naturalised Distribution

The plant is becoming widely naturalised in south-eastern Queensland. It has also been recorded from north-eastern New South Wales and the coastal districts of central Queensland.

Habitat

A common weed of roadsides, old gardens, disturbed sites, waste areas and waterways (i.e. riparian areas) in the higher rainfall areas of sub-tropical eastern Australia. It has also been reported from open woodlands, rainforest margins and coastal fore-dunes in this region.

In Hawaii it has become naturalised in dry disturbed sites, while in Florida it has invaded undisturbed pine forests and other open woodlands.

Habit

A slender, but long-lived (i.e. perennial), climbing plant that grows up over supporting vegetation adn can reach up to 10 m or more in height.

Distinguishing Features

a climbing plant with slender twining stems.

its once-compound leaves have several to numerous pairs of small leaflets.

Flowers and Fruit

The small whitish, pink, mauve or purplish pea-shaped flowers (about 10 mm long) are borne in dense slightly elongated clusters. These flower clusters are usually arranged on stalks (i.e. peduncles) that emanate from the leaf forks (i.e. axillary racemes). Individual flowers have five small green sepals, which are fused together at the base into a short tube (i.e. calyx tube). They have a large upper petal (i.e. standard), two side petals (i.e. wings) and two lower petals that are fused together and folded lengthwise (i.e. a keel).

The fruit is a flat and realtively broad pod (20-35 mm long and 12-15 mm wide) with a sharp point (i.e. beak). These pods are sparsely covered in hairs and have a rough texture (i.e. they are tuberculate). When mature, these brown pods split open and curl back to reveal several (usually 3-7) oval-shaped (i.e. ellipsoid) seeds. The very distinctive seeds (5-7 mm long and 4-5 mm wide) are bright scarlet-red in colour with a large black spot. They are smooth in texture, glossy in appearance and generally remain on the plant for some time (i.e. several months).

Reproduction and Dispersal

This species reproduces mainly by seed. These seeds are thought to be mostly bird-dispersed, but it is likely that they are also spread along waterways during floods and in dumped garden waste.

Environmental Impact

Crab's eye creeper (Abrus precatorius subsp. africanus) is regarded as an environmental weed in New South Wales and south-eastern Queensland. It is currently of most concern in north-eastern New South Wales, where it is a relatively recent introduction, but it is much more common and widespread in south-eastern Queensland.

This species has been reported in various types of open woodlands (e.g. banksia and eucalypt forests) in the coastal districts of northern New South Wales. It appears on the regional environmental weed list for north-eastern New South Wales, developed by the Bushland Friendly Nursery Scheme, and hence also appears on several local environmental weed lists in this region (e.g. in Ballina Shire, Lismore City and Coffs Harbour City councils).

Crab's eye creeper (Abrus precatorius subsp. africanus ) is also one of the "exotic vines and scramblers" whose invasion of native plant communities is listed as a "key threatening process" in New South Wales. Such species are of concern because they may act as transformer species, altering the nature of the plant communities that they invade. Exotic vines and scramblers smother existing vegetation, both in the ground layer and canopy, altering the light climate and suppressing the regeneration of native species.

Until recently, crab's eye creeper (Abrus precatorius) was often regarded as being native to south-eastern Queensland, or as being introduced here from northern Queensland, and was not treated as a serious threat. However, now that it is known to be an exotic form of this species, crab's eye creeper (Abrus precatorius subsp. africanus) is beginning to be treated with more concern as a potentially invasive plant. Populations of this weed are becoming more common and widespread in the region, and are often seen in riparian areas and revegetation sites in suburban Brisbane (e.g. along Enoggera Creek in The Gap and the along the Brisbane River in St. Lucia). Infestations are also being actively controlled on Fraser Island.

Crab's eye creeper (Abrus precatorius) is also regarded as a serious invasive weed in some parts of the USA, particularly throughout the central and southern parts of Florida, where it is noted to establish well in disturbed drier forests and spread rapidly after fires.

Other Impacts

The seeds of this species are extremely toxic to humans and livestock (e.g. cattle and horses).

Legislation

This species is not declared or considered noxious by any State or Territory.

Similar Species

Because of its very distinctive seeds, crab's eye(Abrus
precatorius) is rarely confused with other species. However, the introduced
form of this species (i.e. Abrus precatorius subsp.
africanus) is extremely similar to the native form which
grows in northern Australia (i.e. Abrus precatorius subsp.
precatorius). These two subspecies can be distinguished by the
following differences:

Giddy giddy (Adenanthera abrosperma), a native tree from
northern Queensland, has almost identical red and black seeds. However, this
plant can be easily distinguished by its arborescent habit, globular flower
clusters, and twice-compound (i.e. bipinnate)
leaves.

Fact sheets are available from Department of Employment, Economic Development and Innovation (DEEDI) service centres and our Customer Service Centre (telephone 13 25 23). Check our website at www.biosecurity.qld.gov.au
to ensure you have the latest version of this fact sheet. The control methods referred to in this fact sheet should be used in accordance with the restrictions (federal and state legislation, and local government laws) directly or indirectly related to each control method.
These restrictions may prevent the use of one or more of the methods referred to, depending on individual circumstances. While every care is taken to ensure the accuracy of this information, DEEDI does not invite reliance upon it, nor accept responsibility for any loss or damage caused by actions based on it.